There over 3500 species of mosquitoes
throughout the world with 150 of them residing in the United States. In
Illinois, there are over 55 species with about 18 of them commonly caught
in our of district.

All mosquitoes found within the District's boundaries belong
to one of two groups:Floodwater
mosquitoes or permanent and stagnant water mosquitoes.Membership in one or the other group is
dependent on the type of environment in which the female mosquito chooses to
lay her eggs.

FLOODWATER MOSQUITOES, such as Aedes vexans, lay
their eggs on dry ground in areas that are subject to flooding following
rainfall.These eggs lay
dormant until sufficient inundation occurs to initiate hatching.Hatching is synchronized, and development
from egg to a blood-feeding adult can occur within 7 to 10 days.Areas within the District serving as
production sources for such mosquitoes include swamp and marsh margins, roadside
ditches, poorly maintained detention ponds and the floodplains of the Des
Plaines River and associated creek systems.Floodwater mosquito species are the most bothersome and prolific nuisance mosquitoes biting District residents during the daytime and nighttime.

STAGNANT WATER MOSQUITOES lay their eggs directly on the
water surface, either singly or in a cluster or raft.The production sources are constantly replenished with the next
generation's eggs, resulting in constant emergence of new adults during the
course of the summer.Human biting species occurring within the
District include Coquillettidia perturbans, Anopheles punctipennis,
and Anopheles quadrimaculatus.More importantly, however, are species in the Culex pipiens
complex, which are known to be competent vectors of Saint Louis Encephalitis,
West Nile Virus and are believed to be responsible for both amplification of
the virus in birds and transmission to man.This District therefore places a high priority on the suppression of the
members of this medically important group.

In order to survive all mosquitoes must have water to complete
its life cycle. Each species has its own preference for the type of water
in needs. Water quality can range from fresh rain water to sewage and
mosquitoes will lay their eggs any where water is found (from plastic
containers, tires to tree holes, edges of ponds & marshes). Because they can exploit a variety of different aquatic
habitats mosquitoes are very successful organisms. Some are even adept at
exploiting organically polluted water areas devoid of natural mosquito predators
and parasites.

It is the female mosquito that bites humans and other animals
(mammals, birds, reptiles and amphibians). Males only feed on plant
juices. Females require a blood meal in order for her eggs to develop and
be viable. Some females prefer only one food source while others will feed
on a variety food sources.

Mosquitoes undergo complete metamorphosis meaning they go
through four stages (egg, larva, pupa, adult). During the summer,
mosquitoes typically go from egg to adult in 7-10 days but this will vary
depending on temperature, humidity, and other environmental factors. Males
tend to live a very short time, usually about one week; and females live about
one month again depending on environmental factors. Below is a diagram of
the mosquito life cycle with a description of life stage.

Mosquito Morphology

Adult mosquitoes only have one pair
of wings (forewings), the second pair of wings have been reduced to small organs
called Halteres. Halteres are used as balancing organs during flight.
The link below is diagram taken from Darsie and Ward, 1981.

Mosquito larva and pupa complete
their part of the life cycle in an aquatic environment. They have adapted
special structures to aid them. The larvae have a siphon on their eighth
segment which they use as a snorkel to gather air at the surface of the water.
The pupa have two structures coming off of the posterior region of the thorax
called Trumpets. These trumpets are used in the same manner as the siphons
in the larval stage. They also have "paddles" on the last segment of the
abdomen which aid in swimming.

One of the most important reasons for mosquito control is that
mosquitoes are capable of transmitting diseases. Diseases that are
transmitted by insects and other arthropods are called Arboviruses. These
insects and arthropods that are capable of spreading diseases are called
Vectors. A few diseases that are transmitted by mosquitoes are listed
below:

Arboviruses

Worldwide

United States

Yellow Fever

~200,000 cases with 30,000 deaths each year

rare in the United States

Dengue Fever

50-100 million cases each year. Average
case fatality rate is 5%

100-200 cases each year - introduced to U.S.
by travelers

St. Louis Encephalitis

Worldwide distribution

4478 cases from 1964 - present - 3 to 30%
fatality rate

Eastern Equine Encephalitis

200 cases from 1964 - present - 35% fatality
rate

West Nile Virus

~9000 cases with 240 deaths in 2003

Non - Arboviruses

Malaria

300-500 million cases with more than 1
million deaths each year

1200 cases each year - most cases are
immigrants and travelers from malaria risk areas

Dog Heartworm

Worldwide distribution

Causes blockages in the heart and the vessels surrounding the
heart in your dog and is treatable if diagnosed in time.

Occasssionally, heartworm can occur in humans with no
known significance. In the last 20 years, 80 cases have been reported
from Florida.

You can find more in depth information about these diseases at
the following website: